The wildfire in Malibu has hit a former nuclear research site, and some activists are worried about radiation in the smoky air

The Woolsey Fire approaches homes on November 9, 2018 in Malibu, California. At least 75,000 homes have been evacuated in Los Angeles and Ventura counties due to two fires in the region.Photo by David McNew/Getty Images

Part of the Santa Susana Field Laboratory burned in the fire. The research site had a partial nuclear meltdown in 1959 that contaminated the soil and groundwater with radioactive particles and carcinogens.

State and federal officials do not believe toxic chemicals were released into the air as a result of the recent fire.

But some activists say the fire could very well have caused toxins to mix with the smoke and ash in the air.

The Woolsey Fire outside Los Angeles has burned part of a former nuclear research site.

State and federal officials believe the Woolsey Fire, which forced the entire city of Malibu to evacuate, has not caused any radioactive materials to be released from the research facility. But some activists say toxic chemicals from Santa Susana likely contaminated the surrounding smoke and ash.

In the 1940s, the US government began using Santa Susana to test nuclear weapons and rockets. The facility spans more than 2,800 acres on the border of Los Angeles and Ventura Counties. A partial nuclear meltdown in 1959 caused radioactive material and carcinogens to contaminate the surrounding soil and groundwater, and some reports say the meltdown released more radioactive material than any other nuclear accident in US history.

In a Friday statement, the Department of Toxic Substances Control said its scientists and toxicologists "reviewed information about the fire's location and do not believe the fire has caused any releases of hazardous materials that would pose a risk to people exposed to the smoke."

A follow-up statement released Tuesday said staff members had tested the site over the weekend and did not find elevated levels of radiation. The department said it would conduct more air and soil testing over the next several days.

A group of physicians says the damage to Santa Susana could affect residents' health

Some activists are concerned that the area surrounding Santa Susana may not be not safe for residents. Physicians for Social Responsibility Los Angeles, a group that advocates for the elimination of nuclear and environmental threats, says the fire likely released toxins into the air.

"We know what substances are on the site and how hazardous they are," Dr. Robert Dodge, the organization's president, said in a statement. "These toxic materials are in SSFL's soil and vegetation, and when it burns and becomes airborne in smoke and ash, there is real possibility of heightened exposure for area residents."

A 1997 study found that workers at the Santa Susana site had elevated rates of cancer in connection with nuclear activity at the complex. If radioactive particles were released into the air, it is possible that similar health effects could be observed among nearby residents.

However, Kai Vetter, a professor of nuclear engineering at University of California Berkeley, told the Los Angeles Times that the health effects of smoke inhalation are greater than any potential danger from radioactive particles in the air.

"Although there is a possibility that radioactive materials — accounted for or not — could be dispersed through the fire and the smoke plume, the risk for health effects due to radiation is expected to be small," Vitter said.

This Feb. 12, 2009 photo shows buildings at the old Rocketdyne facility, the Santa Susana Field Laboratory, in the Simi Valley area near Los Angeles. Reed Saxon/AP

The physicians' group also criticized the California Department of Toxic Substances Control for having "no public confidence," and pointed out that state lawmakers commissioned an independent review panel in 2015 to monitor the department's public outreach, fiscal management, and enforcement of hazardous-waste laws.

The clean-up process at Santa Susana has faced delays

Most of the Santa Susana site is owned by Boeing, though NASA oversees one area and the US Department of Energy leases a portion as well. A Boeing spokeswoman told the Los Angeles Times that more than 50% of the company's property at Santa Susana burned.

A 2007 order instructed the three parties to finish cleaning up the site by 2017, but those clean-up efforts have repeatedly hit delays. In August, the Ventura County Star reported another delay: an action plan that was supposed to come out in the first half of 2019 is now behind schedule.

These delays have drawn backlash from local community members. Last year, a group of parents called for tougher clean-up standards, claiming their children's cancer diagnoses were linked to the nuclear research site. The group delivered a petition with more than 17,000 signatures to state officials.

Investigators have not yet determined what caused the Woolsey Fire. Last week, however, utility company Southern California Edison told state regulators that an outage was reported at one of its substations a few minutes before the fire began. The outage was in the same area where Woolsey broke out; in fact, the substation is located within the Santa Susana complex.